Merge pull request #36 from bdunahu/bdunahu

Add fetch stage implementation, tests, program loading, DTO object
Base classes plus base tests for Instruction Fetch stage with a default program

1 files changed, 100 insertions, 0 deletions

diff --git a/tests/if.cc b/tests/if.cc
new file mode 100644
index 0000000..5c1b645
--- /dev/null
+++ b/tests/if.cc
@@ -0,0 +1,100 @@
+#include "if.h"
+#include "cache.h"
+#include "controller.h"
+#include "dram.h"
+#include "instrDTO.h"
+#include <catch2/catch_test_macros.hpp>
+
+class IFPipeFixture
+{
+  public:
+	IFPipeFixture()
+	{
+		Dram *d;
+
+		d = new Dram(this->m_delay);
+		// 0xC00 is a nop
+		p = {0xC000, 0xC001, 0xC002, 0xC003};
+		d->load(p);
+
+		this->c = new Cache(d, this->c_delay);
+		this->f = new IF(nullptr);
+		this->ct = new Controller(this->f, this->c, true);
+	}
+	~IFPipeFixture()
+	{
+		delete this->ct;
+		delete this->c;
+	};
+
+	/**
+	 * Fetch a clean line not in cache.
+	 */
+	void fetch_through(InstrDTO &instr)
+	{
+		int i;
+		Response r;
+
+		for (i = 0; i < this->m_delay + 1; ++i) {
+			r = this->ct->advance(instr);
+			// check response
+			CHECK(r == BLOCKED);
+		}
+		this->fetch_cache(instr);
+	}
+
+	/**
+	 * Fetch a line in cache.
+	 */
+	void fetch_cache(InstrDTO &instr)
+	{
+		int i;
+		Response r;
+
+		for (i = 0; i < this->c_delay; ++i) {
+			r = this->ct->advance(instr);
+			// check response
+			CHECK(r == WAIT);
+		}
+		r = this->ct->advance(instr);
+		// check response
+		CHECK(r == OK);
+	}
+
+	int m_delay = 3;
+	int c_delay = 1;
+	std::vector<signed int> p;
+	Cache *c;
+	IF *f;
+	Controller *ct;
+};
+
+TEST_CASE_METHOD(IFPipeFixture, "fetch returns single instuction", "[if_pipe]")
+{
+	InstrDTO instr;
+	int expected_cycles;
+
+	expected_cycles = this->m_delay + this->c_delay + 2;
+	this->fetch_through(instr);
+
+	CHECK(instr.get_if_cycle() == expected_cycles);
+	REQUIRE(instr.get_instr_bits() == this->p[0]);
+}
+
+TEST_CASE_METHOD(IFPipeFixture, "fetch returns two instuctions", "[if_pipe]")
+{
+	InstrDTO instr;
+	int expected_cycles;
+
+	expected_cycles = this->m_delay + this->c_delay + 2;
+	this->fetch_through(instr);
+
+	CHECK(instr.get_if_cycle() == expected_cycles);
+	REQUIRE(instr.get_instr_bits() == this->p[0]);
+
+	expected_cycles += this->c_delay + 1;
+	this->fetch_cache(instr);
+
+	CHECK(instr.get_if_cycle() == expected_cycles);
+	REQUIRE(instr.get_instr_bits() == this->p[1]);
+}